Lubricant oil composition and lubrication method

Patent metadata

Field	Value
Publication number	US-10883064-B2
Application number	US-201716086500-A
Country	US
Kind code	B2
Filing date	Mar 13, 2017
Priority date	Mar 23, 2016
Publication date	Jan 5, 2021
Grant date	Jan 5, 2021

Abstract

Provided are; a lubricating oil composition excellent in fuel saving performance, seizure resistance, wear resistance, fatigue lifetime and shear stability, which contains a base oil (A), an olefin polymer (B) having a number average molecular weight of 1,000 or more and 12,000 or less, and a specific sulfur compound (C) and wherein the content of all sulfur atoms based on the total amount of the composition is 1.2% by mass or more and 2.5% by mass or less; and a lubrication method using the lubricating oil composition.

First claim

The invention claimed is:

1. A lubricating oil composition, comprising:
a base oil (A) comprising a mineral and a synthetic oil, wherein the synthetic oil comprises at least one ester oil and optionally at least one poly-α-olefin;
an olefin polymer (B), which is an ethylene-propylene copolymer having a number average molecular weight of 1,500 or more and 7,000 or less;
a sulfur compound (C) represented by formula (3):
R 1 —S m1   (1)

wherein R 1 represents a divalent hydrocarbon group, m 1 represents an integer of 4, n 1 represents an integer of 10 or less, p represents an integer of 1 or more and 4 or less, and R 3 and R 4 each represent a monovalent hydrocarbon group;
at least one thiadiazole compound (D1); and
optionally, polymethacrylate,

wherein:
the content of the base oil (A) based on the total amount of the composition is at least 80% by mass,
the content of the synthetic oil relative to the base oil (A) ranges from 5.96% by mass to 20% by mass, with the balance of the base oil (A) being the mineral oil,
the content of the at least one poly-α-olefin based on the total amount of the composition is 9% by mass or less,
the content of the olefin polymer (B) based on the total amount of the composition ranges from 3% by mass or to 8% by mass,
the content of the sulfur compound (C) based on the total amount of the composition ranges from 0.2% by mass to 1.5% by mass,
the content of the thiadiazole compound (D1) based on the total amount of the composition ranges from 1.5% by mass to 4.5% by mass,
the content of polymethacrylate based on the total amount of the composition is 5% by mass or less, and
the content of all sulfur atoms based on the total amount of the composition ranges from 1.59% by mass to 2.5% by mass.

2. The lubricating oil composition according to claim 1 , wherein the content of sulfur atoms in the sulfur compound (C) relative to all sulfur atoms is 1% by mass or more and 20% by mass or less.

3. The lubricating oil composition according to claim 1 , further comprising a sulfur compound (D2) having a structural unit represented by the following general formula (2):
R 2 —S m2   (2)

wherein R 2 represents a divalent hydrocarbon group, and m 2 represents an integer of 1 or more and 3 or less.

4. The lubricating oil composition according to claim 1 , further comprising a phosphorus acid ester (E).

5. The lubricating oil composition according to claim 4 , wherein the ratio by mass of sulfur atoms to phosphorus atoms (S/P ratio) is 8 or more and 16 or less.

6. The lubricating oil composition according to claim 1 , having a kinematic viscosity at 100° C. of 6 mm 2 /s or more and 11 mm 2 /s or less.

7. The lubricating oil composition according to claim 1 , which is for a gear oil.

8. A lubrication method, comprising lubricating a device with the lubricating oil composition of claim 1 .

Assignees

• Idemitsu Kosan Co

Inventors

• Sunagawa Yoji

Classifications

• C10M2205/02

  containing acyclic monomers · CPC title

• C10N2040/135

  Steam engines or turbines · CPC title

• C10N2030/68

  Shear stability · CPC title

• C10M2205/0285

  used as base material · CPC title

• C10N2040/252

  Diesel engines · CPC title